Railway signaling



R. A. MCCANN.

RAILWAY SIGNALING.

APPLlcATmN FILED ocr. 4, 1919.

Patented May 10, 1921.

2 SHE,E'I'S-SHEET I.

R. A. McCANN. RAILWAY SIGNAUNG. APPLICATION FILED. OCT, 4, 1913.

Patented May 10, 1921. l

2 SHEETS-SHEET 2.

'raar orricr..

. RONALD A. IVICCANN, OF SWISSVALE,PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SW'ISSVALE, PENNSYLVANIA, CORPORA- TION OF PENNSYLVANIA.

RAILWAY SIGNAIING.

T0 aU whom may concern. l

Be it'known that I, RONALDA. MGCANN, a citizen of the United States, residing at Swissvale, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway Signaling, of which the following is a specification.

My invention relates to railway signaling, and particularly to signaling for stretches of single track over which traific moves in both directions.

In signaling of this character, it is customary to provide a series of signals governing traffic in one direction, a line relay for each signal, each of which relays is normally controlled by the relay for the signal next in advance, andauxiliary relays for at times removing the line relays lfrom such control. One feature of my invention ris the provision of novel and peculiarly effective circuits for the control ofsuch auxiliary relays.

I will describe one form of signaling system embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawings,V Figures 1 and 2, when placed end to end in the order named, constitute a diagrammatic view showing one form of signaling system embodying my invention.

Referring to the drawings, the reference characters 1 andla designate the track rails of a stretch of single track between two passing sidings lL and M, and over which track traffic moves in both directions.v

The stretch A-K between the twopassing sidings is divided into a plurality of sections by means of insulated joints 2,- and each section is provided with a track circuit comprisingas usual a track battery 5 and a track relay designated'by the reference character T, with a suitable exponent. As here shown, the track circuit for each section except for section'C-D and F-G comprises a battery at one end of the section and a relay at the other end. In the case of sections C-D and F-Gr, however, a track battery is located adjacent the mid dle of the section and the section is provided with two track relays located adjacentthe ends of the section, respectively.

Trafiic` through the stretch from east to Specification of Letters Patent.

Patented Mayl, 1921` serial No. 328,484. Y

west is governed by signals S', S3 and S5, whereas traffic through `the stretch from west to east is governed by signals S2, S4 and SG. `As here shown, each signal is located adjacent the junction of two track sections except the end signals S' and S2, which signals are located at the outer ends of the two end sections for the stretch.

Each signal is controlled by a line relay which is designatedbythereference character' R, with the same exponent as that used for the corresponding signal. Each signal is provided with a circuit which is controlled by the corresponding line relay. Consider-A ing signal S2, for example, the control circuit is from a battery P2, through wires 8 and i, contact 5 of relay R2', wire 6, operat-v ing mechanism of signal S2, wire 7, contact 8 of relay R3, and wires 9 and 10 to battery P2. Tnasmuch as contacts 5 and 8 are closed only when relay R2 is energized, it follows that signal S3 will indicate stop when relay R3 is denergized and proceed when this relay is energized. The controlling circuit lfor each signal is similar to the circuit just traced for signal S3.

The line relay for each signal (except as hereinafter noted) is normally controlled by the line relay for the signal next in advance governing traffic in the same direction, and by the track relays for all track circuits lying between the two signals. Considering line relay R,"for example, the controlling circuit for this relay is from bat` tery P3, through wires 3 and 11, contact 12 of relay R2, wires 13 and 14, contact 15 of track yrelay T2, wire '16, contact 1'? of track relay T10, wire 18, winding of relay R',

common wire 0 and wire 10 to battery P2. Line relay R2 is similarly controlled by track relays T5, T 75, lT7 and Tia-nd by line relay R2. ALine relay R5, however', is controlledonly by track relays T', T2, T2 and T4, there being no line relay involved in the circuit for this relay.y The control of the line relays for they signals governing traiiic from west to east is similar to the control of the line relays for signals S', and S5.

Means are provided for at times removing line relay R from control by line relay R2', this means being an auxiliary Vrelay X3, which is normally denergized, but which tact 12 of relay R3. This shunt passes from l signal indicates stop. It will be seen, therefore, that relay X3 can be picked up only when signal S3 indicates proceed, relay R3 is de'e'nergized, and both track relays T3 and T3 are denergized. Relay X3 is provided with a holding circuit which passes from battery P3, through wires 3 and 81, contact 32 of relay X3, wires 33 and 27, winding of relay X3, wire 28, back contact 29 of relay R3, and wires 30 and 10 to battery l P3. This circuit is, of course, closed only when relay X3 is energized and relay R3 deenergized.

Signal S5 is provided with a similar auX- iliary relay X3, which, when energized, removes relay R3 from control by relay R5. Signals S4 and Ss are provided with auX- iliary y relays X4 and X4 for similar purposes.

The operation of the system is as follows:

Assuming first that train passes through the stretch moving toward the west, it will be observed that as soon as such train passes the point K, it will cause track relay T10 to open. This track relay opens at contact 17 the circuit for relay R', so that signal S moves to the stop position. Track relay T1o also opens the circuit for relay RG, so that signal SG moves to the stop position. Relay RG then opens the circuit for relay Rt, and relay R4 in turn opens the circuit for relay R2, so that signals S4 and S2 also move to the stop position. As the train passes out of section- H-K and into section Gr-H, track relay T10 becomes energized and track relay T3 is opened, but this causes no change in the signal controlling circuits. As the train enters section F-G, it opens track relay TS, which in turn opens the circuit for line relay R3, so that signal S3 starts to 'move toward the stop position. While the train is bridging the point Gr and before Contact Q3 opens, the pick-up circuit for auxiliary relay X3 becomes closed. As soon as relay X3 becomes energized, the stick circuit for this relay is closed and remains closed as long as line relay R3 remains denergizcd. hen the rear of the train passes point G, track relay T9 closes so that relay R again becomes energized and so causes signal S `vjito return to the proceed position.

As the train proceeds through section F-G, it causes track relay T7 to open and subsequently permits track relay T3 to close, but

this causes no change in the controlling circuits for the signals. lVhen the entire train has passed out of section F-G, track relay T7 closes, but line relay R6 remains open because its circuit is open at the lower contact of relay X3. As the train passes through sections Eel? and D-E, track relays T6 and T5 are opened successively, thereby holding relays R3 and R4 open and so holding signals S3 and S4 at stop. As the train passes point D, signal S5 moves to the stop position. Relay X5 becomes energized by virtue of circuits which are similar to those for relay X3, so that after the rear of the train has passed point D relay R3 becomes energized, whereupon signal S3 returns to the proceed position. As soon as relay R3 closes, the stick circuit for relay X3 is opened, but the consequent opening-of this latter has no e'ifect on relay R because the circuit for the latter relay is then closed at contact 12 of relay R3. The opening of relay X3, however, permits relay R6 to close so that signal SG returns to the proceed position. When the rear of the train passes point A, signals S2, S4, and S5 returned to the proceed position. VVhenrelay closes, relay X5 opens, thus again permitting relay R3 to be energized through the front contact of relay R3. The parts of the system are thus restored to the positions in which they are shown in the drawing.

The operation of the apparatus during the passage of a train from west to east will be understood from the foregoing explanation. As soon as such train enters the section 1 -B, it causes signals S2, S3, S8 and S to assume the stop position. This movement of signal S3 opens contact Q3, so that when the train subsequently bridges the point Gr, the pick-up circuit for relay X3 is not closed; in other words, relay X3 becomes energized only when a train passes through the stretch moving toward the west.

The present invention is directed particularly to the pickeup circuit for each of the auxiliary relays X. One important feature of the invention is the provision of the back contact 29 (see relay X3) of line relay in this pick-up circuit. This contact prevents relay X3 from being energized unless relay R3 opens, due to the entrance of a train into section F-G. In other words, if relay R3 should stick in the closed position when a westbound train enters section FG, relay X3 would remain open, so that signal S would continue to indicate stop until the rear of the train has passed signal S3.

Another feature of the invention is the provision of the two back contacts 23 and 25 operated by track relays T3 and T3, respectively, in the pick-up circuit for the auX- iliary relay X3. Assuming that contact 25 of relay T3 were omitted from this circuit, it will be evident that failureof track battery b for section Ill-G, which wouldnpermit track relay T8 to open,.would cause relay R3 to open and so would cause relay X3 to close. An eastbound train entering the stretch A--K would then fail-to cause signal S'l to assume the stop position. By controlling the pick-up circuit for relay X3 by both track relays T3 and T3, however, itwill be' seen that the simultaneous failure oftwo track batteries would be necessaryfto ycause false energization of relay X3, and the simultaneous failure of two batteries is, of course, not likely to occur.

Where in the accompanying claims I have used the term block, I mean the space between two adjacent signals governing trai'lic in the same direction, as, for example, the space between signals S and S3, or between signals S3 and S5. Of these two blocks, the block Gr-K is the rear and the block D-G is the forward block.

Although I have herein shown and described only one form of signaling system embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and Scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track, a plurality of signals located at intervals for governing traflicin one direction through said stretch, a line 'relay for each signa-l, means for normally controlling each line relay by the line relay for the signal next in advance governing traffic in the same direction, track circuits for the stretch for controlling said line relays, an auxiliary relay for each line relay arranged when energized to remove such line relay from its control of the line relay for the signal next in the rear, a pick-up circuit for each auxiliary relay including a back contact of the corresponding line relay, and a holding circuit for each auxiliary relay including said back contact of the corresponding line relay and a front contact of the auxiliary relay.

v 2. In combination, a stretch of railway track, two signals governing traflic in one direction along said stretch, a line relay for each signal, means for normally controlling the line relay for the rear signal by the line relay for the forward signal, track circuits for said stretch for controlling said line relays, an auxiliary relay for the forward signal arranged when energized to remove the corresponding line relay from its control of the line relay for the rear signal, a pickup circuit for said auxiliary relay including a back contact of the corresponding line .rela-y, and a holding circuit for said aux- Viliary relay including said back contact of the corresponding line relay and a front Contact of the auxiliary relay.

8. In combination, arailway track divided into twoblocks, track circuits forsaid blocks, a Signal for each block, a line relay .for the forward signal, means forv controlling said line relay by the track circuits for the Aforward block, means for normally Vcontrolling said rearsignal by said line relay 4. In combination, a railway track di-- vided into two blocks, track circuits for said blocks, a signal for each block, a line relay for the forward signal, means for controlling said line relay by the track circuits for the forward block, means for -normally controlling said rear signal by Vsaid line relay and by the track circuits for the rear block,

an auxiliary relay for said forward signal arranged when energized to remove the rear signal from control by said line relay; a pick-up circuit for said auxiliary relay including a back contact of said line relay, a back contact of the track relay for the forward-track circuit of the rear block, and a back contact of the track relay for the rear track circuit of the forward block; and a holding circuit for said auxiliary relay including a front contact thereof and said back contact of said line relay. Y

5. In combination, a railway track divided into two blocks, track circuits for said blocks, a signal for each block, a line relay for the forward signal, means for controlling said line relay by the track circuits for the forward block, means for normally controlling said rear signal by said line relay and by the track circuits for the rear block, an auxiliary krelay for said forward Signal Varrangedwhen energized to remove the rear blocks, a signal for each block, a line relay for the forward signal, means for controlling said line relay by the track circuits for the forward block, means for normally controlling said rear signal by said line relay and by the track circuits for the rear block, an auxiliary relay for said forward signal arranged when energized to remove the rear signal from control by said' line relay; a pick-up circuit for said auxiliary relay including a back contact of said line relay, a 4back Contact of the track relay for the for- 5 Ward track circuit of the rear block, a back contact of the track relay for the rear track circuit of the forward block and a contact operated by said forward Signal and closed or' open according as such signal indicates 1'0 proceed or stop; and a holding circuit for said auxiliary relay including a front contact thereof and said back contact of said line relay.

In testimony whereof I afiX my signature in presence of two Witnesses.

A. HERMAN WEGNER, J. A. STULL. 

